Atrial fibrillation is the most common sustained arrhythmia and has an increasing incidence and prevalence in the United States and worldwide. Catheter ablation of atrial fibrillation is potentially curative and has become a common procedure. A cornerstone of catheter ablation of atrial fibrillation is isolation of the pulmonary veins according to current guidelines (Heart Rhythm. 2012; 9(4):632-696). Pulmonary vein isolation alone has a high incidence of recurrent atrial fibrillation (Circulation. 2003; 108:2355-2360). Identification of additional regions of the atrium to treat with ablation are difficult to determine and controversial.
Additional regions may include linear ablation (Circulation. 2004; 110:2996-3002) and ablation of complex fractionated atrial electrograms (J Am Coll Cardiol. 2004; 43:2044-53).
Three-dimensional mapping of arrhythmias is commonly performed to identify the mechanisms of an arrhythmia and to facilitate targeted ablation of the arrhythmia. Mapping of stable arrhythmias is commonly performed. Atrial fibrillation is an unstable arrhythmia making traditional point-by-point activation mapping not possible. Sources and mechanisms of atrial fibrillation are controversial and in theory include multi-wavelet reentry (Moe G K, Abildskov A J: Am H J. 1959: 59-70), focal sources of electrical activity (Haïssaguerre M, et. al.: N Engl J Med 1998; 339:659-66), and spiral waves (rotors) of electrical activity (Skanes, et. al.: Circulation, 1998; 98(12):1236-1248). In order to effectively create a map to identify the mechanisms of atrial fibrillation, a catheter or catheter system that has a widely dispersed set of electrode sensors is required to acquire simultaneous signals from disperse areas of the atrium. Ablation of atrial fibrillation seeks to disrupt the mechanisms of atrial fibrillation to facilitate restoration of sinus rhythm. Currently, techniques that attempt to determine the sources and mechanisms of atrial fibrillation are inadequate due to a limited distribution of electrode sensors in the atrium to fully define the mechanism of atrial fibrillation.
Existing catheter designs for collecting electrograms include basket shaped catheter designs. One example of a basket catheter design is the Constellation catheter (Boston Scientific, Natick, Mass., USA). This design partially fulfills the need of a large number of contact electrodes to cover a large area of the one of the two atria. This design is limited by being expensive to manufacture, having limited coverage with electrodes at the proximal and distal poles, having limited contact to multiple areas in the atrium, being difficult to estimate size relative to the atrium, and that the size is not adjustable. When deployed in the left atrium, there is minimal contact with the interatrial septum and regions close to the right pulmonary veins.